This project is designed to provide information important to the understanding of basic questions about perceptual and cognitive processes occurring during a fixation in skilled reading. A computer system will be set up for tracking the reader's eyes as he reads passages displayed on a computer-controlled cathode-ray tube (CRT). This permits rapid manipulation of the stimulus available to the subject during a fixation, with reference to the fixation point. Using this system, the text display will be modified at each fixation, and during fixations, to delete or make available certain aspects of the original stimulus at certain regions of the visual field. It is assumed that if deleting some aspect of the visual stimulus produces deterioration in the person's reading performance, this is evidence that the deleted stimulus is normally used in reading. If such a deletion has no effect on reading performance, however, that aspect of the stimulus is probably not used during reading. Complete records of eye fixation locations and durations will be kept together with scores from comprehension tests for the passages read. College students with superior reading skill will serve as subjects. Specific questions to be investigated are: What is the size and shape of the region from which skilled readers pick up useful visual information during a fixation? What cues are typically used to identify words in various parts of the visual area during a fixation? When is visual information acquired during a fixation, and is there any sequence to its acquisition? Do relations exist between fixation characteristics (location and duration) and the linguistic structure of the text?